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为研究汶川震区滑坡堆积体土石混合坡面细沟水流曼宁系数的变化过程及其影响因素,在两级坡面(坡度为34°、36°)、三级流量(4、8、12L/min)、四种石土比(质量比为0∶1、1∶3、1∶2、1∶1)的组合条件下,进行室内放水冲刷试验。结果表明,曼宁系数n随冲刷历时呈先缓慢增大、再迅速增大、最后急速减小的变化趋势。不同石土比条件下,n平均值大小顺序为n(1∶3)>n(1∶2)>n(1∶1)>n(0∶1)。n随流量的增大而减小,但变幅不大。水深h与n呈幂函数正相关关系。雷诺数Re与n关系不显著,弗劳德数Fr与n呈显著的幂函数负相关关系。n/h与Re呈显著的幂函数负相关关系,n/h与Fr关系不显著。研究结果为建立汶川震区滑坡堆积体坡面土壤侵蚀模型提供了理论依据。
In order to study the variation of Manning coefficient of rill flow on the soil-rock mixed slope of Wenchuan earthquake zone and its influencing factors, / min), four kinds of soil to stone ratio (mass ratio of 0: 1, 1: 3, 1: 2, 1: 1) combination conditions, indoor water scouring test. The results show that the Manning coefficient n increases slowly first, then increases rapidly and finally decreases rapidly. Under different conditions of stone ratio, the average value of n is n (1: 3)> n (1: 2)> n (1: 1)> n (0: 1). n decreases with the increase of the flow rate, but the amplitude is not big. Water depth h and n are power function positive correlation. The relationship between Reynolds number and n is not significant, and the Froude number Fr and n are negative power relations. n / h and Re showed a significant power function negative correlation, n / h and Fr relationship was not significant. The results provide a theoretical basis for establishing the slope soil erosion model of landslide accumulation in Wenchuan earthquake area.